A degree of frost is a non-standard unit of measure for air temperature meaning degrees below melting point (also known as "freezing point") of water (32 degrees Fahrenheit or 0 degrees Celsius). "Degree" in this case can refer to degree Celsius or Fahrenheit.
When based on Celsius, 0 degrees of frost is the same as 0°C, and any other value is simply the negative of the Celsius temperature. When based on Fahrenheit, the conversion is a bit more complicated, as 0 degrees of frost is equal to 32°F. Conversion formulas:
Rankine is a thermodynamic (absolute) temperature scale named after the Glasgow University engineer and physicist William John Macquorn Rankine, who proposed it in 1859. (The Kelvin scale was first proposed in 1848.)
The symbol for degrees Rankine is °R (or °Ra if necessary to distinguish it from the Rømer and Réaumur scales). Zero on both the Kelvin and Rankine scales is absolute zero, but the Rankine degree is defined as equal to one degree Fahrenheit, rather than the one degree Celsius used by the Kelvin scale. A temperature of −459.67 °F is exactly equal to 0 °R.
The Royal Society of London for Improving Natural Knowledge, commonly known as the Royal Society, is a learned society for science, and is possibly the oldest such society still in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London". The Society today acts as a scientific advisor to the British government, receiving a parliamentary grant-in-aid. The Society acts as the UK's Academy of Sciences, and funds research fellowships and scientific start-up companies.
The Society is governed by its Council, which is chaired by the Society's President, according to a set of Statutes and Standing Orders. The members of Council and the President are elected from and by its Fellows, the basic members of the Society, who are themselves elected by existing Fellows. There are currently 1,314 Fellows, allowed to use the postnominal title FRS (Fellow of the Royal Society), with 44 new Fellows appointed each year. There are also Royal Fellows, Honorary Fellows and Foreign Members, the last of which are allowed to use their postnominal title ForMemRS (Foreign Member of the Royal Society). The current Royal Society President is Sir Paul Nurse, who took up the position on 30 November 2010.
Rømer (also Roemer) is a temperature scale named after the Danish astronomer Ole Christensen Rømer, who proposed it in 1701.
In this scale, the zero was initially set using freezing brine. The boiling point of water was defined as 60 degrees. Rømer then saw that the freezing point of pure water was roughly one eighth of the way (about 7.5 degrees) between these two points, so he redefined the lower fixed point to be the freezing point of water at precisely 7.5 degrees. This did not greatly change the scale but made it easier to calibrate by defining it by reference to pure water. Thus the unit of this scale, a Rømer degree, is 100/52.5 = 40/21 of a kelvin (or of a Celsius degree). The symbol is sometimes given as °R, but since that is also sometimes used for the Rankine scale, the other symbol °Rø is to be preferred. The name should not be confused with Réaumur.